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LIVING IN THE ENVIRONMENT 17THMILLER/SPOOLMAN
Chapter 11
Sustaining Aquatic Biodiversity
Case Study: Protecting Whales: A Success Story… So Far (1)
• Cetaceans: Toothed whales and baleen whales
• 8 of 11 major species hunted to commercial extinction by 1975
• 1946: International Whaling Commission (IWC)• Quotas based on insufficient data• Quotas often ignored
Case Study: Protecting Whales: A Success Story… So Far (2)
• 1970: U.S. • Stopped all commercial whaling• Banned all imports of whale products
• 1986: IWC moratorium on commercial whaling• 42,480 whales killed in 1970• 1500 killed in 2009• Norway, Japan, and Iceland ignore moratorium
We Have Much to Learn about Aquatic Biodiversity
• Greatest marine biodiversity• Coral reefs• Estuaries • Deep-ocean floor
• Biodiversity is higher• Near the coast than in the open sea • In the bottom region of the ocean than the surface
region
Natural Capital: Marine Ecosystems
Fig. 8-5, p. 172
Natural Capital: Freshwater Systems
Fig. 8-15, p. 181
Human Activities Are Destroying and Degrading Aquatic Habitats
• Marine • Coral reefs• Mangrove forests• Seagrass beds• Sea-level rise from global warming will harm coral
reefs and low-lying islands with mangrove forests• Ocean floor: effect of trawlers
• Freshwater• Dams• Excessive water withdrawal
Natural Capital Degradation: Area of Ocean Bottom Before and After a Trawler
Fig. 11-2, p. 252
Invasive Species Are Degrading Aquatic Biodiversity
• Invasive species • Threaten native species• Disrupt and degrade whole ecosystems
• Two examples• Asian swamp eel: waterways of south Florida • Lionfish in the Atlantic
Invasive Lionfish
Fig. 11-3, p. 254
Science Focus: How Carp Have Muddied Some Waters
• Lake Wingra, Wisconsin (U.S.): eutrophic• Contains invasive species
• Purple loosestrife and the common carp
• Dr. Richard Lathrop• Removed carp from an area of the lake
• This area appeared to recover
Lake Wingra in Madison, Wisconsin
Fig. 11-A, p. 255
Case Study: Invaders Have Ravaged Lake Victoria
• Loss of biodiversity and cichlids
• Nile perch: deliberately introduced
• Frequent algal blooms• Nutrient runoff• Spills of untreated sewage• Less algae-eating cichlids
• Water hyacinths
Natural Capital Degradation: The Nile Perch In Lake Victoria
Fig. 11-4a, p. 254
Water Hyacinths in Lake Victoria
Fig. 11-5, p. 255
Population Growth and Pollution Can Reduce Aquatic Biodiversity
• More noise and crowding from humans
• Nitrates and phosphates, mainly from fertilizers, enter water• Leads to eutrophication
• Toxic pollutants from industrial and urban areas
• Plastics
Hawaiian Monk Seal
Fig. 11-6, p. 256
Climate Change Is a Growing Threat
• Global warming: sea levels will rise and aquatic biodiversity is threatened• Coral reefs• Swamp some low-lying islands• Drown many highly productive coastal wetlands
• New Orleans, Louisiana, and New York City
Overfishing and Extinction: Gone Fishing, Fish Gone
• Marine and freshwater fish • Threatened with extinction by human activities more than any
other group of species
• Commercial extinction: no longer economically feasible to harvest a species
• Collapse of the Atlantic cod fishery and its domino effect
• Fewer larger fish
• More problems with invasive species
Natural Capital Degradation: Collapse of the 500 year old Cod Fishery Off the Canadian Coast
Fig. 11-7, p. 257
Started using bottom trawlers in late 1950s.
Case Study: Industrial Fish Harvesting Methods
• Trawler fishing
• Purse-seine fishing
• Longlining
• Drift-net fishing
• Bycatch problem
Legal Protection of Some Endangered and Threatened Marine Species
• Why is it hard to protect marine biodiversity? 1. Human ecological footprint and fishprint are expanding
2. Much of the damage in the ocean is not visible
3. The oceans are incorrectly viewed as an inexhaustible resource
4. Most of the ocean lies outside the legal jurisdiction of any country
Case Study: Holding Out Hope for Marine Turtles
• Threats to the leatherback turtle• Trawlers and drowning in fishing nets• Hunting • Eggs used as food• Pollution• Climate change
• Fishing boats using turtle excluder devices
• Communities protecting the turtles
Sea Turtle Species
Fig. 11-9, p. 262
An Endangered Leatherback Turtle is Entangled in a Fishing Net
Fig. 11-10, p. 262
Establishing a Global Network of Marine Reserves: An Ecosystem Approach (1)
• Marine reserves• Closed to
• Commercial fishing• Dredging• Mining and waste disposal
• Core zone• No human activity allowed
• Less harmful activities allowed• E.g., recreational boating and shipping
Establishing a Global Network of Marine Reserves: An Ecosystem Approach (2)
• Fully protected marine reserves work fast• Fish populations double• Fish size grows• Reproduction triples• Species diversity increase by almost one-fourth
• Cover less than 1% of world’s oceans• Marine scientists want 30-50%
Individuals Matter: Creating an Artificial Coral Reef in Israel
• Reuven Yosef, Red Sea Star Restaurant• Coral reef restoration• Reconciliation ecology-humans
should increase biodiversity in human-dominated landscapes
• Treatment of broken coral with
antibiotics
Protecting Marine Biodiversity: Individuals and Communities Together
• Oceans 30% more acidic from increased carbon dioxide in atmosphere and increased temperature
• Integrated Coastal Management • Community-based group to prevent further
degradation of the ocean
Estimating and Monitoring Fishery Populations Is the First Step
• Maximum sustained yield (MSY): traditional approach
• Optimum sustained yield (OSY)
• Multispecies management
• Large marine systems: using large complex computer models
• Precautionary principle
Some Communities Cooperate to Regulate Fish Harvests
• Community management of the fisheries
• Co-management of the fisheries with the government• Government sets quotas for species and divides the
quotas among communities• Limits fishing seasons• Regulates fishing gear
Government Subsidies Can Encourage Overfishing
• Governments spend 30-34 billion dollars per year subsidizing fishing
• Often leads to overfishing
• Discourages long-term sustainability of fish populations
Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity
• Need labels to inform consumers how and where fish was caught
• 1999: Marine Stewardship Council (MSC)• Certifies sustainably produced seafood
• Proper use of sustainable aquaculture• Plant eating fish best -- Tilapia
Solutions: Managing Fisheries
Fig. 11-11, p. 267
We Can Preserve and Restore Wetlands
• Laws for protection• Zoning laws steer development away from wetlands• In U.S., need federal permit to fill wetlands greater
than 3 acres
• Mitigation banking• Can destroy wetland if create one of equal area• Ecologists argue this as a last resort
Human-Created Wetland in Florida
Fig. 11-12, p. 268
Case Study: Can We Restore the Florida Everglades? (1)
• “River of Grass”: south Florida, U.S.
• Damage in the 20th century• Drained • Diverted• Paved over• Nutrient pollution from agriculture• Invasive plant species
• 1947: Everglades National Park unsuccessful protection project
Case Study: Can We Restore the Florida Everglades? (2)
• 1990: Comprehensive Everglades Restoration Plan (CERP)1. Restore curving flow of ½ of Kissimmee River2. Remove canals and levees in strategic locations3. Flood farmland to create artificial marshes4. Create 18 reservoirs to create water supply for
lower Everglades and humans5. Recapture Everglades water flowing to sea and
return it to Everglades
• Already weakened by Florida legislature
The World’s Largest Restoration Project
Fig. 11-13, p. 269
Case Study: Can the Great Lakes Survive Repeated Invasions by Alien Species?
• Collectively, world’s largest body of freshwater
• Invaded by at least 162 nonnative species• Sea lamprey• Zebra mussel• Quagga mussel• Asian carp
Zebra Mussels Attached to a Water Current Meter in Lake Michigan
Fig. 11-14, p. 271
Asian Carp from Lake Michigan
Fig. 11-15, p. 271
Using an Ecosystem Approach to Sustaining Aquatic Biodiversity
• Edward O. Wilson• Complete the mapping of the world’s aquatic
biodiversity• Identify and preserve aquatic diversity hotspots• Create large and fully protected marine reserves• Protect and restore the world’s lakes and rivers• Ecological restoration projects worldwide• Make conservation financially rewarding
Three Big Ideas
1. The world’s aquatic systems provide important ecological and economic services, and scientific investigation of these poorly understood ecosystems could lead to immense ecological and economic benefits.
2. Aquatic ecosystems and fisheries are being severely degraded by human activities that lead to aquatic habitat disruption and loss of biodiversity.
3. We can sustain aquatic biodiversity by establishing protected sanctuaries, managing coastal development, reducing water pollution, and preventing overfishing.